Authorities, planners and designers are concerned with providing safer systems for transport with an aim to avoiding injury and death of road users.
For example there is great concern with reducing the numbers of accidents that occur on roads. Legislators are constantly aiming to improve vehicle safety and there is a trend to focus on road safety including signs, layout and lighting.
Additionally procedures tend towards sustainability and cost awareness. A cost effective means of providing safety on roads, highways and runways, or indeed pedestrian walkways is to provide lighting.
In particular given most vehicles provide their own lighting for a number of years retro-reflectors such as those known as “cats-eyes” have provided a cost-effective, efficient and simple means of lighting paths so as to indicate. These provide a passive reflector that is mounted in the road and reflects incident light from a vehicle headlamp. (CATSEYE is acknowledged as a registered trade mark.)
However, even with such reflectors sometimes roads can be hazardous for drivers, especially at sharp bends or curves and they only provide limited illumination levels.
Another disadvantage is that traditional “cats eye” road studs are only active when incident light from a vehicle headlamp is reflected to the driver and for this to occur the vehicle has to be relatively close to the “cats eye” road stud with direct line of sight from the vehicle headlamp to the “cats eye” road stud and from the “cats eye” road stud to the driver. The light reflected back from a cats eye does not effectively illuminate the road surface because the light is reflected back to the source of light, that is the headlamp. Therefore with such traditional “cats eye” road studs there is often no way that a driver can judge the lie of the road further ahead than the vehicle headlamp can illuminate.